1. Field of the Invention
The present invention relates to a photoreceptor unit in which a photoreceptor drum is housed in a housing.
2. Description of the Related Art
Generally in the field of image forming apparatuses such as electrophotographic copying machines and laser printers, there has been proposed a variety of photoreceptor units in which a photoreceptor drum and its accessory elements are housed in a housing.
This kind of photoreceptor unit requires a mechanism for stabilizing the rotation of the photoreceptor drum. Since the unit is dimensionally increased when a flywheel is adopted as this mechanism, compact braking members have been widely used.
For example, there has been a known photoreceptor unit as shown in FIG. 9, where a braking member 6 is placed between an end surface of a flange 2 of a photoreceptor drum 1 and an inner surface of a housing 5 in a state in which it is compressed in the axial direction of the photoreceptor drum. However, since a load due to the braking member 6 is exerted in the axial direction of the photoreceptor drum 1 in this photoreceptor unit, a side segment 5a of the housing 5 is deformed in the direction of arrow "d", and this has led to the problem that a support shaft 3 receives a moment in the direction of arrow "e", consequently displacing the position of the photoreceptor drum 1.
In an attempt at solving the aforementioned problem, there has also been a photoreceptor unit as shown in FIG. 10, where the support shaft 3 is formed of one member that penetrates the photoreceptor drum 1 and is placed between the side segments 5a and 5a of the housing 5. However, when the support shaft 3 is formed of one member that penetrates the photoreceptor drum 1, the weight of the entire unit becomes heavy and a cost increase results.
There has further been a known photoreceptor unit as shown in FIG. 11, where a braking member 7 is arranged between an outer peripheral surface of a flange 2 of a photoreceptor drum 1 and a housing opening inner peripheral surface 5b over approximately a half of the circumference of the photoreceptor drum. However, this unit also has the problem that a load due to the braking member 7 is effected in the direction of arrow "f", causing a displacement of the photoreceptor drum 1.